Immune depression is a common clinical sequelae in certain chronic and acute bacterial, viral and parasitic infections. In other diseases toxemia may reduce bone marrow capacity with resultant anemia and abnormalities of the immune system. The immune system is responsible for host resistance to diseases, and immunodepression or immunosuppression can predispose infection with one or more infectious agents, commonly known as opportunistic infections. A loss of immune system activity often results in serious and life-threatening diseases. Such functional abnormalities may be present in any of the cellular or humoral components of the immune system, e.g., granulocytes, lymphocytes, complement, antibody, etc. Animals having dysfunctional immune systems may also be at an increased risk of malignancy.
Inmunodeficiencies may result from many etiologies including a primary hereditary genetic abnormality (e.g., Chediak-Higashi Syndrome, Severe Combined Immunodeficiency, Chronic Granulomatous Disease, DiGeorge Syndrome); or, may be acquired as a result of accidental exposure, e.g., to radiation, heavy metals, insecticides, or, from therapeutic intervention e.g., chemotherapy with glucocorticoids or radiation therapy, or acquired as a results of infection e.g., with HIV, CMV, Mycobacteria, or a parasite. Patients with a primary or an acquired immunodeficiency would benefit from methods for stimulating the immune system.
Diseases may also result from loss of regulatory control within the immune system. For example autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjogren's syndrome, and type II diabetes may result from improper recognition of "self" tissues as "foreign". Treatments may include generalized non-specific immune suppression that can result in an increase in the incidence of infections and malignancy. Methods to compensate for decreased anti-microbial resistance during chemotherapy (or radiation therapy) are of great medical importance.
Immunological stimulation, even in healthy individuals, may aid in the treatment or prevention of disease. For example, stimulating an immune response to a vaccine, referred to herein as vaccine augmentation, could improve the duration or strength of protection afforded by the procedure. Also, specific immunization with tumor antigens has been shown in certain circumstances to result in tumor remission. Drugs used in treatment of cancer and infection have significant side effects, and use of an immunostimulatory agent could make it possible to reduce the dose of the a drug to a less toxic level.
Thus, there is a need in the art for compositions and methods that modulate, i.e., stimulate or depresses, the immune system. Ideally, a candidate compound or method would be (i) capable of stimulating or suppressing immunity, dependent upon the immune status of the patient at the time of treatment; and, (ii) be able to restore a natural balance to a dysfunctional immune system. Quite surprisingly, the present invention fulfills these and other related needs.